Drill cutter retaining ring



June 9, 1931. F. SCOTT 1,309,074

DRILL CUTTER RETAINING RING Filed May 4,- ,1929' M AV 4 Fig. 2

A TTURXE Y Patented June 9 1931 UNITED STATES ATENT OFFICE FLOYD L. SCOTT, OF HOUSTON, TEXAS, ASSIGNOR TO HUGHES TOOL COMPANY, OF

HOUSTON, TEXAS, .A CORPORATION OF TEXAS DRILL currnn nnramme 1mm Application filed Hay 4.192s; Serial No. 360,371.

' My invention relates to means for retaining a drill cutter rotatably upon its hearing. It is particularly adapted for use with conical shaped cutters, such as are now used in drillin rock or other hard formation in well drilling operations.

The cutters upon which the invention is employed are mounted upon a bushing or bearing which has to be threaded or otherwise engaged u on the end of a supporting in or shaft. he bushing is frusto-conical in shape and the cutter is mounted on the bushing to surround the end of the bushing and the shaft. The cutter is retained in position rotatably upon the bushing by a retaining ring screwed into the base of the cutter behind the large diameter of the bushlDifiiculty has been experienced in operating cutters thus mounted because of the reat strains to which the device is subected in use tending to force the cutter 7 off the end 0 the bushing and tearing the retaining ringfrom' its seat. Further, it is necessar in screwing the assembled cutter and bus 'ng upon the shaft that the cutter and bushing be held non-rotatably together while the bushing is screwed upon the shaft. An opening is provided in the side of the cutter extending into the bushing so that a pin may be introduced into the said bushing to rotate it about the shaft in screwing it thereon. This opening must be comparatively large to receive a pin strong enough to unscrew the'cutter. and bushing afterit has become fixed in the shaft in operation. The openin cannot be large if it is to extend throug the ring or the ring will be unduly weakened.

Myinvention has for its object, the rovision of a cutter of the type describe in which the retaining ring may be formed of suflicient length to be firmly attached to its seat in the cutter andisnot greatly weakened by the wrench pin opening.

I desire to form a large wrench in opening along the large diameter of e cutter and still not materially weaken the ring by means of which the cutter is held upon the bmhinge I In the drawings herewith, Fig. 1 is a central longitudinal section through a drill cutter showing my improved means for looking the cutter upon its bushing.

Fig. 2 shows a side and end elevation of the retaining ring.

In illustratlng my invention, I have shown a cutter having a body 1 of frusto-conical shape having its base beveled somewhat at 2 to form a gauge surface. The cutter has circumferential rows of teeth 3 thereon of ordinary construction.

The cutter has an interior frusto-conical shaped socket 4 therein to fit about a bushing 5. Said bushing has a reduced neck 6 connecting with its base, said neck terminatlng approximately flush with the base of the cutter. A shoulder 7 is thus formed on said bushing to bear against a retaining ring 8 which secures the cutter on said bushing.

The cutter socket 4 has a threaded seat 9 of welding material 10 by means of which the ring is rigidly held in position.

The ring 8 is formed of suflicient lengthto make a strong attachment with the cutter. It has at one point, along its inner end, a semicircular notch 11, formed to allow the passage of a wrench pin of the usual construction.

The wrench pin is used to rotate the bushing to screw it upon its shaft when the cutter has been assembled thereon and locked in position. An openin 12 is formedradially through the wall 0 openinglis threaded at 13 to receive a stop w on the wrench is not in use. The

the wrench pin. 7

In forming the notch in the rin it is first screwed firmly is inserted throng the opening 12 in the cutter and a mark is made upon the ring by said tool to show where the notch should Y be. The ring is then unscrewed and the notch is formed and the ring a ain screwed in The notch is not eep enou h in t ing has a recess 14 to receive the end of 0 ring to materially weaken'it and t e the cutter and this i into its seat an a tool openin 12 may be large enough to receive a pin arge and strong enough to unscrew the cutter and bushing from the pin without danger of breaking the wrench. It is to he understood that the rotation of the well drill in the well tends to screw the bushings so tightl upon the cutter shafts as to practice y reeze the bushing on the shaft and great force must be exerted upon the bush in in unscrewing it from the said shaft.

he opening 12 is closedby a threaded plug of the usual construction, not shown, extendin short of the bushing 5 to prevent mud MIC? slush from entering the bearing, but allowing rotation of the cutter on the bushing.

The construction thus described difiers from prior similar Constructions in that provision is thus made for a long retaining ring, which cannot be forced from its lockmg position to allow the cutter to be lost in use. Also, the locking ring is not'materiall weakened even thou h a large wrenc in opening is formed 1n the cutter and bus in What I c aim as new is:

1. In a drill cutter, a frusto-conical bush ing threaded internally to screw upon the end of a shaft a reduced neck on said bushing, a cutter fitting over and enclosing one end of said bushing, a retainin ring shaped to fit about the neck of said ushlng, and screw into a threaded seat in said cutter,

there being an arcuate notch on the inner end of said ring to allow passage of a wrench pin to engage within a registering openin in said cutter and 'nto a recess in sai bushing.

2. In a drill cutter, a :frusto-conical bushing threaded internally to screw upon the end of a shaft, a reduced neck on saidbushing, a cutter fitting over and enclosing one end of said bushing, a retaining ring sha ed to fit about the neck of said bushing, an ter, there being an arcuate notch on the inner end of said ring to allow passage of a a wrench pin to engage within a registering opening in said cutter and into a recess in said bushing, and means to hold said retaining rin rigidly in position. n

3. In a rill cutter a bushin ,-a shoulder on said bushing, a frusto-conica shaped cutter enclosing one end of said bushing, means to retain said cutter on said bushing including a ring screwed within said cutter and engaging a shoulder on said bushing, said cutter, and bushing having registering opening therein to receive a wrench pin, and a notch formed in said ring to register with said wrench pin openings.

In testimony whereof I hereunto aflix my signature, this 16th day of April, A. D.

FLOYD L. scorn screw into a threaded seat in said cut- 

